Consider it part of the rebuilding process. Find a role for the guy that suits his strengths and don't dwell on the amount of his contract. It is what it is. If you can dump his contract, great. If not, just keep putting the guy in the best possible scenarios to be productive, even if not as an everyday player.
Another way to look at it: Get as much value as you can out of the guy, even if that value still never matches his contract. If you just dump him while you still have his salary on your books, or give up a quality prospect just to have his salary off your books, you're simply digging a deeper hole for yourself than the one you already inherited from the previous owner.